<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<input type="button" value="alert警告框" onclick="alert('我是警告框')">
<input type="button" value="confirm确认框" onclick="confirm('我是确认框')">
<input type="button" value="prompt提示框" onclick="prompt('我是提示框')">
</body>
</html>